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add decimal math to EVM

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1m1-github/EVMPlus

 
 

WINNER OF ETHONLINE HACKATHON 2023: https://www.youtube.com/live/ASnWiZ4moA8?si=3giCUgUHv5ImbF8X&t=45m32s

EVM+

Add decimal math to the EVM

Decimal

A Decimal defined as $c * 10^q$ (as a golang struct)

with $c$ (coefficiant) and $q$ (exponent) are taken from the stack and interpreted as int256 (via twos complement).

OPCODE defs

0xd0 DECADD a + b (ac, aq, bc, bq, precision) -> (cc, cq)
0xd1 DECNEG -a (ac, aq) -> (bc, bq)
0xd2 DECMUL a * b (ac, aq, bc, bq, precision) -> (cc, cq)
0xd3 DECINV 1/a (ac, aq, precision) -> (bc, bq)
0xd4 DECEXP exp(a) (ac, aq, precision, steps) -> (bc, bq)
0xd5 DECLN ln(a) (ac, aq, precision, steps) -> (bc, bq)
0xd6 DECSIN sin(a) (ac, aq, precision, steps) -> (bc, bq)

precision is the # of digits kept. steps for DECEXP and DECSIN are the # of Taylor expansion steps. steps for DECLN is the depth of the continued fractions expansion.

elementary functions

in the smart contract code (or as precompiled smart contracts), we can easily get the following functions:

a^b = POW(a, b) = EXP(b * LN(a))
COS(a) = SIN(TAU/4 - a) // TAU is a constant added by the user to desired precision
TAN(a) = SIN(a) / COS(a)

a^b gives us all polynomials. SIN gives us all of trigonometry.

putting all together, we get all elementary functions.

implementation

  1. define DECADD, DECNEG , DECMUL, DECINV following https://github.com/JuliaMath/Decimals.jl/blob/master/src/arithmetic.jl
  2. DECEXP, DECSIN via Taylor series expansion https://en.wikipedia.org/wiki/Taylor_series#Exponential_function and https://en.wikipedia.org/wiki/Taylor_series#Trigonometric_functions
  3. DECLN via continued fractions https://en.wikipedia.org/wiki/Natural_logarithm#Continued_fractions

use cases

lots of scientific, mathematical, financial, digital art calculations require universal functions such as EXP, LN, SIN. the ability to calculate a^b is considered so basic, that even high school scientific calculators include it. in mathematical finance e.g., going from annualized volatility to daily volatility requires taking the 16th root (a^(1/16)).

these new capabilities will invite large universes of apps into Ethereum.

two functioning example use cases:

  1. Black-Scholes ~ basic formula to value options risk neutrally (https://github.com/1m1-github/go-ethereum-plus/blob/main/tests/EVMPlus/BlackScholes.yul) ~ ca. 32k gas (charged double)
  2. Neuron ~ sigmoid activated single neuron (https://github.com/1m1-github/EVMPlus/blob/main/tests/EVMPlus/Neuron.yul) ~ ca. 24k gas (charged double)

generally, with these OPCODES, users can solve integrals, diff. equations, etc.

testing

testing the correctness of the math itself is trivial. we can achieve as high a confidence as we like by comparing more digits of any calculation. any mistake in any part of the code would contribute in accumulated higher errors in the end result, i.e. if we e.g. get the option price to match a reliable web2 lib value to 100 digits, the chance of error is extremely low. i.e., we can make it as low as the chance of an Eth hash collusion, if we wanted to.

gas

all the above OPCODEs are deterministic, hence the gas cost can be determined. at the same time, the calculations are complex and depend on the input.

it is crucial to have accurate gas costs to avoid energy attacks on nodes.

to this end, i have wrapped the underlying uint256 lib with gas accumulation (https://github.com/1m1-github/go-ethereum-plus/blob/main/core/vm/uint256_wrapped.go). this gives a bottom-up approach to calculating gas, by running the OPCODE.

because the EVM interprator expects the gas cost before actually running the OPCODE, we are running the OPCODE twice. the first run, identical to the second, is to get the bottom-up gas cost, which is then doubled to account for the actual run plus the gas calculation. on top, we add a fixed emulation cost.

this gives an embedded gas calcuation, which works well for complex OPCODEs (see gasEVMPlusEmulate in https://github.com/1m1-github/go-ethereum-plus/blob/main/core/vm/gas_table.go).

to remove the double gas, a future EIP would suggest the following: allow contract code to run whilst accumulating gas (at runtime) and panicking in case of limit breach, without requiring the cost in advance. this only works for contract code that is pure, defined as code that only depends on the user input and the inner bytecode of the contract. pure contracts cannot use state from the chain, nor make calls to other contracts. pure mathematical functions would e.g. be pure contracts. pure contracts are fully deterministic given the input, allowing a user to estimate gas costs offline (cheaper) and the EVM to panic at runtime, without knowing gas in advance.

another method to remove the double gas would be to find (and prove) an upper bound dependent on the inputs much closer than the double.

since the costs depend on the input, a fuzzing would give us close to the worst cases (TODO).

binary vs decimal

most apps created by humans work with decimal values. e.g. 0.1 is a very commonly used number, but cannot be represented in binary finitely. adding the ability to represent any decimal value precisely and do calculations with them, invites lots of common web2 apps into Ethereum.

virtual machine

the EVM is a virtual machine and thereby not restricted by hardware. usually, assembly languages provide OPCODES that are basic due to the basic and binary nature of hardware. in a virtual machine, we have no such limitations and nothing stops us from adding complex OPCODES like EXP and LN. at the same time, we do not want to clutter the OPCODES library. EXP and LN however are universal functions that open the path to: powers, trigonometry, integrals, differential equations, machine learning, etc.

arbitrary precision

The algorithms implemented allow for arbitrary precision. Practically, as we always only have access to a finite amount of resources, the available precision is finite.

The first version allows for 256 bits of precision for the significand and exponent each. This corresponds to single elements of the EVM stack. If there is demand for higher precision, we can relatively easily expand to occupying the entire stack. (todo-if-demand)

plan

  1. run private EVM network from local geth
  2. add DECADD, DECNEG , DECMUL, DECINV
  3. add DECEXP, DECLN, DECSIN
  4. workout, test and analyze gas correctly
  5. write example smart contracts
  6. write EIP

EIP

https://github.com/1m1-github/EthereumEIPs/blob/main/EIPS/eip-7543.md

PR to EIPs repo: https://github.com/ethereum/EIPs/pull/7904/files#diff-909e06a2fa0255eedcfa32be67c39afe5e1d0d0db2f69a8b89b4222a51a09db7

Magicians forum

https://ethereum-magicians.org/t/decimal-math-on-evm/16194

live

at the following url, there is a PoA geth node and miner running on London EVM+: http://35.209.100.125:8555 or ws://35.209.100.125:8556

you can now write Yul smart contracts like in the BlackScholes or Neuron example linked above, using the new OPCODEs, compile with solc --evm-version london --strict-assembly smartcontract.yul >> smartcontract.txt to bytecode and use something like ethers.js to deploy/interact with a EVM+ node.

yes, you could attack it and take control of the PoA account ~ pls do not, it's just for testing/showcasing.

email@1m1.io for gas.

i used this project to test the smart contracts: https://github.com/1m1-github/EVMPlus_TESTING

Go Ethereum

Official Golang execution layer implementation of the Ethereum protocol.

API Reference Go Report Card Travis Discord

Automated builds are available for stable releases and the unstable master branch. Binary archives are published at https://geth.ethereum.org/downloads/.

Building the source

For prerequisites and detailed build instructions please read the Installation Instructions.

Building geth requires both a Go (version 1.19 or later) and a C compiler. You can install them using your favourite package manager. Once the dependencies are installed, run

make geth

or, to build the full suite of utilities:

make all

Executables

The go-ethereum project comes with several wrappers/executables found in the cmd directory.

Command Description
geth Our main Ethereum CLI client. It is the entry point into the Ethereum network (main-, test- or private net), capable of running as a full node (default), archive node (retaining all historical state) or a light node (retrieving data live). It can be used by other processes as a gateway into the Ethereum network via JSON RPC endpoints exposed on top of HTTP, WebSocket and/or IPC transports. geth --help and the CLI page for command line options.
clef Stand-alone signing tool, which can be used as a backend signer for geth.
devp2p Utilities to interact with nodes on the networking layer, without running a full blockchain.
abigen Source code generator to convert Ethereum contract definitions into easy-to-use, compile-time type-safe Go packages. It operates on plain Ethereum contract ABIs with expanded functionality if the contract bytecode is also available. However, it also accepts Solidity source files, making development much more streamlined. Please see our Native DApps page for details.
bootnode Stripped down version of our Ethereum client implementation that only takes part in the network node discovery protocol, but does not run any of the higher level application protocols. It can be used as a lightweight bootstrap node to aid in finding peers in private networks.
evm Developer utility version of the EVM (Ethereum Virtual Machine) that is capable of running bytecode snippets within a configurable environment and execution mode. Its purpose is to allow isolated, fine-grained debugging of EVM opcodes (e.g. evm --code 60ff60ff --debug run).
rlpdump Developer utility tool to convert binary RLP (Recursive Length Prefix) dumps (data encoding used by the Ethereum protocol both network as well as consensus wise) to user-friendlier hierarchical representation (e.g. rlpdump --hex CE0183FFFFFFC4C304050583616263).

Running geth

Going through all the possible command line flags is out of scope here (please consult our CLI Wiki page), but we've enumerated a few common parameter combos to get you up to speed quickly on how you can run your own geth instance.

Hardware Requirements

Minimum:

  • CPU with 2+ cores
  • 4GB RAM
  • 1TB free storage space to sync the Mainnet
  • 8 MBit/sec download Internet service

Recommended:

  • Fast CPU with 4+ cores
  • 16GB+ RAM
  • High-performance SSD with at least 1TB of free space
  • 25+ MBit/sec download Internet service

Full node on the main Ethereum network

By far the most common scenario is people wanting to simply interact with the Ethereum network: create accounts; transfer funds; deploy and interact with contracts. For this particular use case, the user doesn't care about years-old historical data, so we can sync quickly to the current state of the network. To do so:

$ geth console

This command will:

  • Start geth in snap sync mode (default, can be changed with the --syncmode flag), causing it to download more data in exchange for avoiding processing the entire history of the Ethereum network, which is very CPU intensive.
  • Start the built-in interactive JavaScript console, (via the trailing console subcommand) through which you can interact using web3 methods (note: the web3 version bundled within geth is very old, and not up to date with official docs), as well as geth's own management APIs. This tool is optional and if you leave it out you can always attach it to an already running geth instance with geth attach.

A Full node on the Görli test network

Transitioning towards developers, if you'd like to play around with creating Ethereum contracts, you almost certainly would like to do that without any real money involved until you get the hang of the entire system. In other words, instead of attaching to the main network, you want to join the test network with your node, which is fully equivalent to the main network, but with play-Ether only.

$ geth --goerli console

The console subcommand has the same meaning as above and is equally useful on the testnet too.

Specifying the --goerli flag, however, will reconfigure your geth instance a bit:

  • Instead of connecting to the main Ethereum network, the client will connect to the Görli test network, which uses different P2P bootnodes, different network IDs and genesis states.
  • Instead of using the default data directory (~/.ethereum on Linux for example), geth will nest itself one level deeper into a goerli subfolder (~/.ethereum/goerli on Linux). Note, on OSX and Linux this also means that attaching to a running testnet node requires the use of a custom endpoint since geth attach will try to attach to a production node endpoint by default, e.g., geth attach <datadir>/goerli/geth.ipc. Windows users are not affected by this.

Note: Although some internal protective measures prevent transactions from crossing over between the main network and test network, you should always use separate accounts for play and real money. Unless you manually move accounts, geth will by default correctly separate the two networks and will not make any accounts available between them.

Configuration

As an alternative to passing the numerous flags to the geth binary, you can also pass a configuration file via:

$ geth --config /path/to/your_config.toml

To get an idea of how the file should look like you can use the dumpconfig subcommand to export your existing configuration:

$ geth --your-favourite-flags dumpconfig

Note: This works only with geth v1.6.0 and above.

Docker quick start

One of the quickest ways to get Ethereum up and running on your machine is by using Docker:

docker run -d --name ethereum-node -v /Users/alice/ethereum:/root \
           -p 8545:8545 -p 30303:30303 \
           ethereum/client-go

This will start geth in snap-sync mode with a DB memory allowance of 1GB, as the above command does. It will also create a persistent volume in your home directory for saving your blockchain as well as map the default ports. There is also an alpine tag available for a slim version of the image.

Do not forget --http.addr 0.0.0.0, if you want to access RPC from other containers and/or hosts. By default, geth binds to the local interface and RPC endpoints are not accessible from the outside.

Programmatically interfacing geth nodes

As a developer, sooner rather than later you'll want to start interacting with geth and the Ethereum network via your own programs and not manually through the console. To aid this, geth has built-in support for a JSON-RPC based APIs (standard APIs and geth specific APIs). These can be exposed via HTTP, WebSockets and IPC (UNIX sockets on UNIX based platforms, and named pipes on Windows).

The IPC interface is enabled by default and exposes all the APIs supported by geth, whereas the HTTP and WS interfaces need to manually be enabled and only expose a subset of APIs due to security reasons. These can be turned on/off and configured as you'd expect.

HTTP based JSON-RPC API options:

  • --http Enable the HTTP-RPC server
  • --http.addr HTTP-RPC server listening interface (default: localhost)
  • --http.port HTTP-RPC server listening port (default: 8545)
  • --http.api API's offered over the HTTP-RPC interface (default: eth,net,web3)
  • --http.corsdomain Comma separated list of domains from which to accept cross origin requests (browser enforced)
  • --ws Enable the WS-RPC server
  • --ws.addr WS-RPC server listening interface (default: localhost)
  • --ws.port WS-RPC server listening port (default: 8546)
  • --ws.api API's offered over the WS-RPC interface (default: eth,net,web3)
  • --ws.origins Origins from which to accept WebSocket requests
  • --ipcdisable Disable the IPC-RPC server
  • --ipcapi API's offered over the IPC-RPC interface (default: admin,debug,eth,miner,net,personal,txpool,web3)
  • --ipcpath Filename for IPC socket/pipe within the datadir (explicit paths escape it)

You'll need to use your own programming environments' capabilities (libraries, tools, etc) to connect via HTTP, WS or IPC to a geth node configured with the above flags and you'll need to speak JSON-RPC on all transports. You can reuse the same connection for multiple requests!

Note: Please understand the security implications of opening up an HTTP/WS based transport before doing so! Hackers on the internet are actively trying to subvert Ethereum nodes with exposed APIs! Further, all browser tabs can access locally running web servers, so malicious web pages could try to subvert locally available APIs!

Operating a private network

Maintaining your own private network is more involved as a lot of configurations taken for granted in the official networks need to be manually set up.

Defining the private genesis state

First, you'll need to create the genesis state of your networks, which all nodes need to be aware of and agree upon. This consists of a small JSON file (e.g. call it genesis.json):

{
  "config": {
    "chainId": <arbitrary positive integer>,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0,
    "berlinBlock": 0,
    "londonBlock": 0
  },
  "alloc": {},
  "coinbase": "0x0000000000000000000000000000000000000000",
  "difficulty": "0x20000",
  "extraData": "",
  "gasLimit": "0x2fefd8",
  "nonce": "0x0000000000000042",
  "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "timestamp": "0x00"
}

The above fields should be fine for most purposes, although we'd recommend changing the nonce to some random value so you prevent unknown remote nodes from being able to connect to you. If you'd like to pre-fund some accounts for easier testing, create the accounts and populate the alloc field with their addresses.

"alloc": {
  "0x0000000000000000000000000000000000000001": {
    "balance": "111111111"
  },
  "0x0000000000000000000000000000000000000002": {
    "balance": "222222222"
  }
}

With the genesis state defined in the above JSON file, you'll need to initialize every geth node with it prior to starting it up to ensure all blockchain parameters are correctly set:

$ geth init path/to/genesis.json

Creating the rendezvous point

With all nodes that you want to run initialized to the desired genesis state, you'll need to start a bootstrap node that others can use to find each other in your network and/or over the internet. The clean way is to configure and run a dedicated bootnode:

$ bootnode --genkey=boot.key
$ bootnode --nodekey=boot.key

With the bootnode online, it will display an enode URL that other nodes can use to connect to it and exchange peer information. Make sure to replace the displayed IP address information (most probably [::]) with your externally accessible IP to get the actual enode URL.

Note: You could also use a full-fledged geth node as a bootnode, but it's the less recommended way.

Starting up your member nodes

With the bootnode operational and externally reachable (you can try telnet <ip> <port> to ensure it's indeed reachable), start every subsequent geth node pointed to the bootnode for peer discovery via the --bootnodes flag. It will probably also be desirable to keep the data directory of your private network separated, so do also specify a custom --datadir flag.

$ geth --datadir=path/to/custom/data/folder --bootnodes=<bootnode-enode-url-from-above>

Note: Since your network will be completely cut off from the main and test networks, you'll also need to configure a miner to process transactions and create new blocks for you.

Running a private miner

In a private network setting a single CPU miner instance is more than enough for practical purposes as it can produce a stable stream of blocks at the correct intervals without needing heavy resources (consider running on a single thread, no need for multiple ones either). To start a geth instance for mining, run it with all your usual flags, extended by:

$ geth <usual-flags> --mine --miner.threads=1 --miner.etherbase=0x0000000000000000000000000000000000000000

Which will start mining blocks and transactions on a single CPU thread, crediting all proceedings to the account specified by --miner.etherbase. You can further tune the mining by changing the default gas limit blocks converge to (--miner.targetgaslimit) and the price transactions are accepted at (--miner.gasprice).

Contribution

Thank you for considering helping out with the source code! We welcome contributions from anyone on the internet, and are grateful for even the smallest of fixes!

If you'd like to contribute to go-ethereum, please fork, fix, commit and send a pull request for the maintainers to review and merge into the main code base. If you wish to submit more complex changes though, please check up with the core devs first on our Discord Server to ensure those changes are in line with the general philosophy of the project and/or get some early feedback which can make both your efforts much lighter as well as our review and merge procedures quick and simple.

Please make sure your contributions adhere to our coding guidelines:

  • Code must adhere to the official Go formatting guidelines (i.e. uses gofmt).
  • Code must be documented adhering to the official Go commentary guidelines.
  • Pull requests need to be based on and opened against the master branch.
  • Commit messages should be prefixed with the package(s) they modify.
    • E.g. "eth, rpc: make trace configs optional"

Please see the Developers' Guide for more details on configuring your environment, managing project dependencies, and testing procedures.

Contributing to geth.ethereum.org

For contributions to the go-ethereum website, please checkout and raise pull requests against the website branch. For more detailed instructions please see the website branch README or the contributing page of the website.

License

The go-ethereum library (i.e. all code outside of the cmd directory) is licensed under the GNU Lesser General Public License v3.0, also included in our repository in the COPYING.LESSER file.

The go-ethereum binaries (i.e. all code inside of the cmd directory) are licensed under the GNU General Public License v3.0, also included in our repository in the COPYING file.

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add decimal math to EVM

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